Right now I'm trying to port Compare It! to Mac OSX. If it would be OK (working and selling , I could think over WinSync too - it will go faster then.
Did you check Synchronize! tool for OSX (qdea.com)?

I would like to be able to see matched sections side by side. Either by a button or option that automatically rearranges the document, or by independant scroll bars that automatically position the sections side by side.

I compare database scripts between environments, dev, test and prod, but the db script generation process doesn't place the scripts for the same object in the same place in the script.

Are you working on that feature? I bought you app a few weeks ago for comparision and wanted to use it now for merging too. I would need a 3-way-merging showing me my version, a version from another person and the resulting merge in which I can add thinks from the two other ones.

I have a product suggestion. Any chance of an api from windows to call out the capabilities of compareit? This would be useful for an automated build/test process. I use a test language called labview. I can then invoke the api from a system exec call in labview and send in the appropriate options to an api to launch, compare, and merge. This would be very useful for trivial merges.

Another thing that would be helpful would be a dll file that I could also call from labview. That would be cool.

Example, say I have two csv (txt files essentially) written using excel and I want to merge a section of one file into the entirety of the other file but both files are very similar to each other (I'm dealing with this situation presently). When I compare the two files, I would like an option in compareit to tell me that the two files are the same excluding the new small section added, and once I add that small section, I want a message indicating that the files are now identical as I've added all I wish to add of the small section into the similar but not identical larger file.

If this is confusing, send me an email and I can send you two of my files and what I'm trying to accomplish in your tool. Great friggin tool btw. I use it often and I'm trying to convince my team members to start using it.